1. Field of the Invention
The present invention relates to a vehicle slide door apparatus for opening and closing an opening formed on a side portion of a vehicle body by a slide door which moves in a fore-and-aft direction.
2. Description of Related Art
Hitherto, in a motor vehicle of one-box type or the like, the one in which an opening formed on a side portion of a vehicle body is opened and closed by a slide door is in common use. The slide door is adapted to be guided in the fore-and-aft direction by three rails provided in parallel (for example, see JP-A-11-157339). An upper rail and a lower rail of the three rails are provided on the vehicle body, and a remaining center rail is provided on the slide door.
The upper rail and the slide door are connected by an upper arm which extends substantially in a lateral direction, and the lower rail and the slide door is connected by a lower arm which extends substantially in the lateral direction. The upper rail and the lower rail extend in the fore-and-aft direction along an upper side and a lower side of the opening of the vehicle body so as to guide one end of each arm in the fore-and-aft direction. The other end of each arm is fixed to a pillar section of the slide door.
In case of side collision of the vehicle, a load is applied to a vertical center portion of the slide door in the direction toward a cabin, and hence the center portion thereof is bent and deformed so as to project toward the cabin. Since the slide door is guided by arms which can move freely in the fore-and-aft direction with respect to the vehicle body, the door body cannot be arrested sufficiently by the vehicle body in case of the side collision in comparison with a door which is guided by a hinge fixed to the vehicle body side. Accordingly, an intrusion amount of the slide door toward the cabin increases, and hence a safety securement of a passenger becomes relatively difficult. Therefore, a structure stiffness of the door body and the vehicle body portion around the door is increased to secure the safety of the passenger, and consequently, there arises such a problem as a weight of the vehicle body and a manufacturing cost increases.